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Ml 21930 



Lithopone 
and Its Part in Paint 

By 
L. H. Trott 

Asst. Mgr. Technical Service 
The New Jersey Zinc ('nmpany 



Revised January, P):to 



The New Jersey Zinc Company 

(Established 1848) 

160 Front Street, New York 

Products Distributed by 

The New Jersey Zinc Sales Company 

(Incorporated) 



Chicago 



Pittsburgh 



San Francisco 






• I 









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L. 



I 



Before the annual convention of The Master Painters & Decorators Association of Iowa, 
at Fort Dodge, Jan. 20, 1927 



Lithopone and Its Part In Paint 

By L. H. Trott 

The New Jersey Zinc Company 

I HAVE been asked to speak to you on the subject of Lithopone. It is an 
appropriate time to make this pigment the subject of a talk to you 
master painters, for Lithopone has made possible some of the products 
you handle in largest quantities in your daily work, and, whether you realize 
it or not, it has revolutionized the paint-making industry, 

Lithopone is a paint pigment. By many people, a pigment is thought to 
be nothing more than coloring matter. Actually, a pigment is any insoluble 
matter added to the vehicle (either an oil, turpentine, liquid drier, clear 
varnish, a mixture of iIm-, .» a clear lacquer) to give the paint color or 
opacity. There are dark pigments which are used to produce colored paints, 
and white pigments which are used for white paints and as the base for 
light tinted paints. Lithopone is a white pigment and L r i\cs to paint many 
desirable qualities which I shall describe later on in this talk. 

Lithopone has undergone many changes since first produced in this coun- 
try in 1906. These improvements and their significance I shall point out 
as I think you should know Lithopone, since it has a great bearing on your 
materials, your jobs and your profits. I shall try to explain it more by means 
of showing you some exhibits than by depending on words alone. 

First, I want to speak briefly about its manufacture. On this table you 
will see the raw materials: barytes, as mined, coal, zinc oxide and sulphuric 
acid. The first operation is to crush the barytes and the coal and roast them 
together. This yields a black mass called "black-ash" and from it the 
so-called "barium liquor", containing barium sulphide in solution, is obtained 
by leaching with water. In another vat, the zinc oxide is dissolved in 
sulphuric acid. These two solutions are rid of objectionable impurities and 
run together, this operation forming the crude Lithopone. I have two solu- 
tions prepared here one, the barium sulphide, the other, the zinc sulphate, 
and will pour them together. You will see the white, insoluble crude 
Lithopone separate out. 

This crude Lithopone is not suitable for use in paint, and in order to make 
it so it must be processed. It is this processing which ma\ either make or 

3 



THE NEW JERSEY ZINC COMPANY 



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i [Gi RE i. 

PhotomL rogi iphs of White Pigments 
Left, \bove Zinc Oxide Right, Above — Lith«.| 

I I Right, Belon [nei i Pigment 

White I 



Left, Relo* 



break the product. The first step is to wash the crude Lithopone with water, 
filter and dry it, then heat it red-hot in a muflle without letting air get at 
it. It is next quenched L\ d no iping the hot mass into cold water, Then it i- 
ground wet, dried, ground again dry, and packed in bags or barrels. Here 
is some of the finished product. \nd what is it ? It is a compound of 30' , 
zinc sulphide and 70% barium sulphate which is made to precipitate 
in such a \\;n that the pigment after mufllin^ is soft, and can easil) be 
ad so finely that Mi- maximum strength "I the Zin< Sulphide one "I 
the strongesl white pigments known is developed and uniformly distri- 
buted <>w*r i h»* fiiiii'- m 



• • 



LITHOPONE AND ITS PART IN PAINT 



Now that we have some finished Lithopone, let us see what it is like. 

• First, it is non-poisonous, and if you care to taste some as I am doing, you 
need not be afraid of the results. I can assure you that it has been thor- 
oughly sterilized, machine packed, and in all probability has not been 
touched by human hands. However, it is better used in paint than as an 
article of diet, and neither you nor I would care about eating a pound of it 
any more than we would want to eat a pound of sand. 

Lithopone is one of the finest white pigments known, and because of 
some improved methods of handling the microscope and the camera, I can 
show you how these particles actually look and how they compare in size 
with other white pigments. These photographs (Figure I) tell the story, and 
in order that you may see better, from where you are, the relative size of 
the difFerent pigments, I have represented them on this enlarged chart 
(Figure II). The space represents the size of a hole in the finest screen 
made, and in this space is shown the average size of single particles of 
zinc oxide, Lithopone, basic carbonate white lead and a typical inert pig- 
ment. 

Next, let us see what will happen when Lithopone is rubbed up with 
linseed oil and thereby comes a step nearer to what you are most interested 
in — paint. I shall rub some out and spread it on glass. At the same time J 
shall make a rub-out of basic carbonate white lead and will place it on the 
same slide. You can readily see the better color of the Lithopone paste. 

In order to save time I have had made two rub-outs in linseed oil, using 
in each case the same weight of ultramarine blue and the same weight of 
white pigments, the white pigments being this same Lithopone and while 
lead. Placed side by side, these rub-outs show a different color, the Lithopone 
being lighter. This indicates the comparative strength of the two pigments, 
the stronger one, Lithopone, being less blued by the ultramarine. It is the 
test usually made for grading the strength of white pigments. The same 
results are obtained if lamp black is used instead of blue (Figure III). 

Likewise two other slides have been prepared, each containing a rub-out 
of Lithopone and basic carbonate white lead. Both slides have been sub- 
jected to gases that are found in town and city smoke — one slide to hydro- 
gen sulphide gas and the other to sulphur dioxide. You can readily see the 
manner in which the Lithopone has resisted turning off color in contrast 
with the blackening of the lead (Fig. IV), 

M ^B The qualities in Lithopone thai have been discussed so far — strength, 

fineness, intense whiteness, and resistance to sulphur fumes — were all points 



THE NEW JERSEY ZINC COMPANY 



E 



Zinc 
Oxide 



Basic Carbonate 

LlTHOPONC WKITt L.EAD 



Opening in 325 Mesh Screen 



I [GURE II. 
Comparative Particle Sizes of White Pigments and 325 Mesh Screen Opening. 



/ 



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thai led the paint manufacturer to try out the pigment in interior paints. 
I '• u as I'm I hei encouraged \\ h«*n he found Lithopone could be safely mixed 
with any other paint pigment— white or colored; that il was easy to in- 
corporate in most of his vehicles; and thai il made a paint which would 
keep and work well. Just as important to him was the price, and ho found 
this within reason. This combination— quality, workability, cost --resulted 
in his now making practically all his (lal whiles, -loss whiles, light lints, and 
a host of industrial specialties with Lithopone as the chief pigment. H is 
these flat and gloss whites and light tints you are spreading toda} on inte- 
rior walls, and ever} time you paint the walls and ceilings of a 12-foot room 
with two coats of Hat white, you leave aboul 30 pounds of Lithopone be- 
hind. The best enamels, however, are still made with pure zinc oxide. 

Lithopone was limited to interior paints for a long time, for in the begin- 
ning it had a very bad habit. You know what it was. It turned gray 
and nearly black in the sunlight. \\ hy, is still being discussed. What was 
more importanl than tokno* why was to know haw to overcome it. It wa- 
in 1920 that a Lithopone manufacturer found out, and by refining the 
process startled the whole paint world by making Lithopone thai told 
"Old Sol"- "1 ou can shine and shine and I will not gel black in the fare." 



LITHOPONE AND ITS PARI IN PAINT 



STRENGTH 

"ALBALITH" 
SUPER LITHOPONE 

BASIC CARBONATE 
WHITE LEAD 





IK. I RE Ml 



I have exposed some of the old-time Lithopone beside some present-da} 
light-resistanl Lithopone before a lamp thai gives out what i- really con- 
centrated sunlight. Thai is to say, it i^ rich in those rays the ultra-\ iolel 
rays— thai turn lithopone dark if il has an> tendency in thai direction, ^f 
You ran see whal has happened (Fig. \ ). The new light-resistanl Lithopone 
has remained perfectly while and the other has turned black. It "devel- 
oped" much like a photograph. The same effeel can he produced by sun- 
shine. 

What was the significance of this improvement? It meant thai here was 
another while pi-ineni that had possibilities of use in outside paints. You y/ 
will remember thai at thai time six there were onl> two out- 

side white paint pigments used, zinc oxide and white lead. In the pursuit 
of de\ eloping an outside paint from Lithopone it was soon found that when 
liirhl in Ihwed oil the paint dried with too sofl a Glm. Il was then 



I III NEW JERSEY ZINC COMPANY 



GASES IN SMOKE 

EXPOSURE TO HYDROGEN SULPHIDE 



EXPOSED UNEXPOSED 



BASIC CARBONATE 
WHITE LEAD 




"ALBALITH" 
SUPER LITHOPONE 



EXPOSURE TO SULPHUR DIOXIDE 

EXPOSED UNEXPOSED 



DK)> 



BASIC CARBONATE 
WHITE LEAD 



"ALBALITH" 
SUPER LITHOPONE 



I I'. I RE IV. 
8 



i rnmm\i \m> i is i-\k i i\ r\i\ i 



ULTRA-VIOLET LIGHT 

[CONCENTRATED SUNLIGHT] 

EXPOSED 



UNEXPOSED 



"ALBALITH" 
SUPER LITHOPONE 



NON-UGHT-RESISTANT 
LITHOPONE 




FIGURE V. 



necessary to call in the assistance of a white pigment thai dried naturally 
to a hard film. Zinc oxide was pressed into service and the combination 
greatly improved the paint. But Lithopone and zinc oxide, as I showed you 
in the beginning, are ver$ fine pigments and they required the addition of 
a coarser pigment. So the inert pigments— silica, magnesium silicate, or 
barytes, were added to the formula, and it was found that about 20' ; of the 
inert in combination developed a paint which actually wore and weathered 
better, and this amount is now usually inclu 

Such a paint — Lithopone— Zinc Oxide — inert pigment paint carries 
about 60% of pigment and 40% of vehicle when read) to spread, and 
weighs aboul I I ! _- pounds [><t gallon. It has been stated thai an outside 
white house painl should carr\ more nearly 70* , of pigmenl than 60, and 
onl\ M)' , of vehicle instead <>t' to. It i^ contended that an) white pigmenl 
can properly take care of and protecl onl\ a certain amount of linseed oil, 
and any more than this amount weakens the paint film. With the latter 

9 



THE NEW JERSEY ZINC COMPANY 



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LITHOPON1 \M) ITS PART IN PAINT 



i ontention I am in lull accord, but if Lithopone, Zinc ( bride, and inert pig- 
ments constitute the pigmenl portion of a paint onl} 60< ] is aecesssar> for 
t V i w reason : 

Everyone knows that a clear oil will not wear as long out-doors as an oil 
that carries pigment. Oil is both porous and perishable and must be com- 
pletely protected from the weather. The pigment gives this protection b\ 
acting largely in two capacities: 

1. As a sunshade. 

'2. As a series of little plugs. 

Taking up the first consideration, a gallon of paint spread on a house and 
allowed to dry covers a certain area. This is measured in square feet or 
square yards. A portion of this area is occupied by the oil and a portion by 
the pigment. It makes no difference whether there \wre 70 pounds or 60 
pounds of pigment spread for every hundred pounds of paint, but the thing 
that matters is whether or not the pigment occupies enough of the space to 
completely shade or protect the oil spread with it. 

In the second consideration it must be remembered that oil alone forms 
a porous film, and if magnified might be imagined to look like a fine screen. 
There must be a sufficient number of pigment particles present to plug up 
all these openings or pores. Now, if you have a bottle to cork, you purchase 
a cork of a certain size, perhaps one that is J g of an inch in diameter. You 
do not go to the store and ask for a 16th-ounce cork or a cork of any other 
weight, lou are interested primarily in size, space, area, volume, and do 
not care a thing about weight. Lead, as you know, is extremely heavy, 
which means nothing more than that a certain weight occupies relatively 
little space. Therefore, where you are using a lighter pigment, you require 
less pounds to occupy the same or greater space. Thus, in the paint in the / 
can or on the job, you are interested in the VOLUME of the pigment and \/ 
the VOLUME of the vehicle or oil, and it must be this PERCENTAGE BY 
VOLUME that is the accurate gauge of what you need. 

This chart tells the story (Figure VI). The objects to the left of the verti- 
cal line represent cans of third or finish-coat paints that are ready to apply 
— the one, a Lithopone— Zinc Oxide — inert pigment paint containing 
60% by weight of pigment and 40% by weight of vehicle, and the other, a 
straight lead paint containing 70% by weight of pigment and 30% by 
weight of vehicle. The two cans marked A and B show the amount of 
pigmenl and vehicle compared on a weight basis. l!> converting the rela- 
tionship to a volume basis, that is to say, gallons of pigment to gallons of 

11 



THE NEW JERSEY ZINC COMPANY 



y 



vehicle, we find that they appear as shown in the middle two cans marked 
C and D on the chart, the Lithopone— Zinc Oxide— inert pigment paint 
showing 24.5% pigment by volume and 75.5% vehicle and the lead 24% 
pigment b\ volume and 76% of vehicle. Thus, there is practically no dif- 
ference between the two paints when looked at in this way, and you can see 
1 Iml the Lithopone base paint carries sufficient pigment to take care of the 
oil. 

At the right marked E and F, I have shown the volume proportion of 
the pigment to the oil alone, which more nearly represents what actually 
remains on the house, since the turpentine and most of the liquid drier 
disappear into the air. Here the Lithopone-Xin< -< Kide-inert pigment paint 
shows 28% pigment by volume and the lead paint 25.2% by volume. 

The big question you all have in your mind is. "What will this Lithopone 
base paint do?" The immediate effect that you observe on applying it is 
indicated on this Qrsl panel, which shows how much whiter three coats of 
Lithopone base paint are, and how much better it covers than three coats 
of white lead. Being whiter, it yields clearer tints, as is shown on these 
• eding pairs of panels. That it will wear and stay white, you can see 
by the next pair of panels which have been exposed for two years facing 
south. Also in tints, their excellent wearing and color retaining qualities 
will he seen by the last pair of panels. Hut the best proof is the fact that 
thousands of houses have been painted with this type of paint (some of 
these b> yourselves), and have given enlire satisfaction. 

This development — an outside white house paint made on a Lithopone 
base — is the direct result of the improvement in Lithopone which enabled 

it to hold its color in the bright sunlight. 

So far in this talk 1 have made a number of statements. I consider all 
of them facts of a technical nature that you or anyone else can substantiate. 
What I am going to tell you in the next tw o minutes is a matter of record. 

Lithopon* in si made in this country in 1906, has increased in popularity 
& i I hat after twenty years it is being produced in practically as large quan- 
tities as zinc oxide and white lead. In 1925 about 150,000 tons of each of 
■ pigments was made. Figure VII shows th* products available 

(925 at the time the pap* ■■ Inthis reissue of the pamphlet January 

1930) the chart has hem revised to include the lairs! information 1928 . 

ir the largest portion of the Lithopone used has gone into interior 
paints. It has now apparently become of age in its tw r enty-first year and 
able to go out of doors. That it is able to take care of itself in its new 
environment is manifested by an actual check-up which showed thai well 

12 



i irnoroM wi> us p\k i i\ i'\i\i 



« 



Orowth of the 
Lithopone Industry 
in Comparison with 

Zinc Oxide and 
Basic Carbonate White Lead 
1906 to 1928 



g 



UTXOPCNt 

'SlOOOTcws 



Zinc Oxide 
7S00O Tons 



White Leao 
! 1 22.000 Tors 



ZlNCOxiDE 

[ lOaOOOToHS 



Basic Carbonate 

White Lead 

1 I ifl 000 Tons 



1906 



1916 



: Lithopone 
I I45.000TONS 




Zinc Oxide j White Lead 

154000 Tons 151,000 Tons 1925 



Lithopone 
200,500 Tons 



Basic Carbonate 
Zinc Oxide White Lead 

161.000 Tons 144000 Tons 1928 



i [Gl i;i VII. 

Growth of Lithopone Industry in Comparison with Lead Free Zinc Oxide and 
Basic Carbonate White Lead. 1906 L928 

over four-fifths of the paint manufacturers in the country are marketing an 
outside paint made on a Lithopone base. How many painters are using it, 
1 don't know, but if it is being made it is certainly being used and you 
are the men who are using it. 

This relatively recent out-of-door application of Lithopone means its 
still further growth and wider use by the trade. It not only interests the 
Lithopone manufacturer but the profits come right down to where you 
can enjoy your share, for if you use white paint indoors or out — YOU CAN 
BUY MORE SQUARE FEET OF HIDING POWER FOR A DOLLAR 
BY BUYING LITHOPONE BASE PAINT THAN YOU CAN BY BUY- 
ING A PAINT MADE FROM ANY OTHER WHITE PIGMENT 
KNOWN. 



s 



13 



THE NEW JERSEY ZINC COMPANY 



It is this economic aspect that I have attempted to lead up to throughout 
this talk. I have traced the individual characteristics of Lithopone and 
outlined their fitness for the various paints. Like anything else, the more 
familiar you are with the parts that contribute to its merits the better able 
you will be to make use of the whole and to capitalize on this knowledge. 
For this reason I feel that you should KNOW Lithopone in the same way 
that you know sugar, salt and the many other things that you daily apply 
to the needs of your work and your play in order to improve the profits you 
get out of your vocation and from the business of life. 



• • 



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ALBALITH 

The Super-Lithopone 

ALBALITH is a lithopone of proved excel- 
l lence of quality. It possesses remarkable 
uniformity, light resistance, color, brightness 
and fineness of particle size. These outstanding 
qualities give beauty and durability to paint 
films containing proper proportions of Albalith. 
Manufacturers of quality paints use Albalith 
extensively in interior paint of all sorts (gloss 
finishes, flat finishes, mill whites, undei i oaters, 
jikI in exterior paint in conjunction with 
\ \ Vmeri< an Pro* ess Zin< I bride. 



'Newjerse^ 

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